1. Field of the Invention
The present invention relates to an antenna and a communication device having the same, and more particularly, to a small-size multiband antenna suitable for a folder type communication device and a folder type communication device having the same.
2. Description of the Related Art
As wireless communication technologies prevail, various wireless communication applications emerge, along with important issues such as antenna miniaturization for portable communication devices. Commonly, it is necessary for most portable communication devices to achieve multiband operations; however, most portable communication devices achieve multiband operations by exciting resonant modes of their embedded antennas only; therefore, in order to cover operations in low-frequency bands, it is often required to increase the occupied area or volume of the antenna.
In prior art techniques such as those disclosed in Taiwan Patent Publication I258,891, entitled “Mobile Phone Antenna,” and Taiwan Patent Publication I262,620, entitled “An Internal Mobile Phone Antenna,” the planar inverted-F antennas (PIFAs) are designed for application in the folder-type mobile phones, and only the quarter-wavelength resonant modes of the planar inverted-F antennas are excited to cover the required frequency bands. Therefore, the length of the antenna must be extended, resulting in the increase in the occupied area or volume of the antenna.
Hence, it is necessary to provide a multiband antenna and a communication device having the same, which can excite resonant modes contributed by a ground portion of a portable communication device to incorporate the resonant modes of antenna to cover required multiband operations to improve the deficiencies in the prior art technique.